Combine Rescue
Member
But still you can try without capacitors.
If MCU is a live it will work without.
If MCU is a live it will work without.
Electronics -PCB
- Thread starter Mur Huwcun
- Start date
- Location
- North West Wales
my bad, switch was still on!! There’s a minute resistance through one but nothing through the other but it’s not enough to excite the beep on the multimeter!!
- Location
- Foothills of the Quantocks
'Minute' meaning very small or very large resistance?
I would expect them to read the same as they are connected in parallel.
Get them snipped off! batteries are a clean enough source that you shouldn't really need them
Combine Rescue
Member
There will be resistance when capacitors get charge then stop. And again when you swap the probes there should be resistance for the time of discharge and charge with reversed polarity that's normal.
- Location
- North West Wales
Very small. Should of measured it really but I tested them on the buzzer setting
- Location
- Agricultural Engineer, Lancashire
Like others have suggested the capacitors aren't really critical in this operation as it runs from a battery supply which is pretty stable. So they could be removed with little consequence. Interesting thought on the 8 pin package being EEPROM I did wonder if this was the case or if the IC had internal memory. Can't imagine much is needed to store basic tunes? Seems like there are a few people here knowledgeable on electronics which is grand to see. Especially seeing as agriculture is adopting technology in most applications.
- Location
- Foothills of the Quantocks
My guess is that the main ic is actually a dedicated part for the job, and then just reads off a pre-programmed eeprom. Would make sense for the manufacturer as they don't have to bother writing all the program logic, just pop their data onto the eeprom and away they go.
The pinout seems to match, although I can't tell where the clock and data traces go
fermerboy
Member
- Location
- Banffshire
Wow!! You guys are good! How/where do you learn this??
I can do a few bits and bobs with electronics but diagnostic stuff on a PCB is usually beyond me.
I regularly change components on my wind turbine rectifier boards but there is no diagnosing required, its the same problem every time.
I will have a look/go but would really like to be a bit better.
I can do a few bits and bobs with electronics but diagnostic stuff on a PCB is usually beyond me.
I regularly change components on my wind turbine rectifier boards but there is no diagnosing required, its the same problem every time.
I will have a look/go but would really like to be a bit better.
- Location
- Agricultural Engineer, Lancashire
To be fair there are quite a few Youtube videos explaining the circuit components and there uses. The rest I read books for and practical diagnostics on PCB's, remembering that a circuit diagram is a good place to start and learn what each block on the PCB is achieving. The IC (Integrated Circuit) datasheets often give you typical uses and layouts which more often than not the manufacturer of the PCBs has adopted rather than re-invent the wheel so this can help you work out what is going on. I will say without diagrams, complex circuits especially those with Microcontrollers can be time consuming and tricky to fix.
I get the satisfaction of repairing something with a 3p component or even 50p that could have ended up costing hundreds if sent to an outside company or a new part purchased. It soon drives the desire to learn more.
TechWise
Member
- Location
- South Ayrshire, Scotland
I'm quite surprised at the number of people on here who are into electronics as well. I'm 11 months off finishing my PhD in Power Electronics. I've been able to get a few things working again round the farm just by being able to solder very small things. Unfortunately, when it's a microcontroller or memory that has failed, there's really nothing you can do because you don't know what was stored in it. Failed capacitors and voltage regulators can usually be replaced though.
- Location
- North West Wales
A slight update on this. I’ve managed to get it to work!! Unfortunately I’m not 100% sure how. There must be a dry or cracked solder on the board as it came to life while I was testing it and turning it over etc!! 
Combine Rescue
Member
LoL
TheTallGuy
Member
- Location
- Cambridgeshire
Back in my engineering days I knew a test technician whose first approach to any fault was to flex a board one way, then the other & then a sharp rap on the table to test for dry joints. If that didn't work then he had to go back to more conventional approachesA slight update on this. I’ve managed to get it to work!! Unfortunately I’m not 100% sure how. There must be a dry or cracked solder on the board as it came to life while I was testing it and turning it over etc!!
SilliamWhale
Member
A slight update on this. I’ve managed to get it to work!! Unfortunately I’m not 100% sure how. There must be a dry or cracked solder on the board as it came to life while I was testing it and turning it over etc!!
You should have hit it with a hammer in the beginning!
- Location
- North West Wales
Does a toddler throwing it about not count!!!
Combine Rescue
Member
And if still not working - take bigger hammer 
- Location
- Scottish Highlands
A standard engineer's ploy is to lift the machine six inches and drop it! There was a cure for a disfunctional computer printer doing the rounds a few years ago. The advice was to bake one of the boards in a domestic oven for a set time at a set heat. It worked for a lot of people as the feedback proved. Presumably it reflowed the solder.
- Location
- North West Wales
The more I look into these things the more I get interested!! It could be a project for this winter, with lockdown 2 looming it’s not looking very good for my other plan over half term to spend a few days on practicing TiG welding Stainless!!!
TechWise
Member
- Location
- South Ayrshire, Scotland
Funnily enough, I bought a TIG about this time last year and spent a bit of lockdown trying to get into the swing on mild steel. If there's another lockdown, I'll get started on the aluminium. I'm finding it pretty hard going actually. Far harder than any sort of tiny soldering I've ever done and certainly far harder than the MIG. I think the offcuts of aluminium I picked up to practice on might be contaminated so I might pick up some brand new stuff to give me a better start.
- Location
- North West Wales
We have a few different machines at work, while I can set them up and weld reasonably I still want a few days playing about and trying different things. Yes with aluminium you need new offcuts!!